What is the meaning of "Lehischalos"?
Radak: He seemed sick amidst his great desire for her.
Why does it say "Ba'avur Tamar Achoso"?
Malbim: He had no hope to marry her, for she grew up like a daughter among the children. He knew that she and his brothers would not consent that they marry, which would publicize that she was not considered David's child.
Why does it say "Ki Besulah Hi"?
Rashi: She was modest, and did not leave the house [Radak - like the practice of Besulos Yisrael], so Amnon did not know how to fulfill his desire for her.
Radak: This increased his desire for her.
Malbim: She was modest in the palace, and would not come in front of him.
What is the meaning of "va'Yipalei"?
Rashi: It was covered (not known to him, how to arrange to have Bi'ah with her). The Targum of "Ki Yipalei Mimcha" (Devarim 17:8) is Yiskasei.
